This invention relates to the recovery of lead from scrap, from its ore or from compounds thereof wherein the lead, or a soluble compound thereof, is dissolved in an aqueous alkanesulfonic acid and recovered by electrolysis at a lead receptive cathode. More particularly, it involves the electrowinning reduction of lead salts to metallic lead from an electrolyte solution comprising dissolved lead sulfonate and an alkanesulfonic acid.
The net production of metal by electrolysis is known as electrowinning. Electrowinning is carried out by passing a direct electric current through a solution of a reducible metal salt. Zero-valent metal is electrodeposited on the cell cathode while some anodic process, usually oxygen formation, is caused to occur on a couple inert anode. Electrowinning processes are distinct from electroplating processes in that the primary object of electrowinning is to recover metal by net depletion of dissolved metal salts. In electroplating, the primary object of the process is to produce a desirable (e.g., protective or decorative) metal coating, and, for convenience, electroplating processes often employ dissolving metal anodes with compositions similar to that of the metal being electrodeposited. In electrowinning, where, by definition, there is net conversion of dissolved metal salts to zero-valent metal, an inert anode must be used.